EP1957234B1 - Method of attaching a functional element to a flat material and connection between a functional element and a flat material - Google Patents

Description

The invention relates to a method according to the preamble of claim 1 and to a compound according to the preamble of claim 9.

A method for attaching or fixing functional elements, in particular of fasteners such as nuts, bolts or the like on a flat material, for example on a workpiece made of a flat material are known in various designs.

A method for attaching or fixing functional elements and in particular also of connecting elements, such as nuts, bolts or the like. Connecting elements on a flat material or a workpiece made of this material are known in various designs. Thus, in particular, a method is known in which the bonding or fixing of the respective functional element is effected by riveting in the region of a dome-like section produced from the flat material by permanent or plastic deformation, ie by drawing or pressing ( EP 539 793 B1 ). In this known method, after the joining and during the riveting of the rivet collar provided on the functional element, the dome-like section is deformed back in such a way that the diameter of the joining opening in the flat material is reduced and its edge is pressed against the rivet collar to produce a radial pressure ring tension, specifically to achieve this an additional anchoring. This method requires a relatively expensive tool. Furthermore, it has been found that, contrary to expectations, a significant improvement in the anchoring or the tear-out strength of the functional element in the workpiece or in the flat material is not achieved with this method.

From the JP 328514 A Furthermore, a method for setting a rivet nut in a flat material and a corresponding rivet nut is known. According to the rivet nut JP 328514 A is provided on a provided cylindrical Nietbund, namely at an inner periphery of the Nietbundes in the region of the opening, a tapered surface. In addition, the rivet nut has an annular groove on a contact surface in the region of an outer circumference of the rivet collar. The deformation of the rivet collar during riveting does not lead to local deformation and stressing of the flat material due to the bevelled surface on the rivet collar and the correspondingly formed annular groove. The JP 328514 A discloses the features of the preamble of claim 1.

The object of the invention is to provide a method which can be carried out with simplified means and still allows anchoring of functional elements in a flat material with high tear resistance. To solve this problem, a method according to claim 1 is formed. A compound is the subject of claim 9. Advantageous embodiments of the method are given in the dependent claims 1-8.

In the invention, the attachment of the respective functional element on the flat material or on a workpiece made of the flat material is done likewise in the region of a dome-like portion or at a joining opening formed at the base of this section by riveting the respective Nietbundes, d. H. by joining and plastic deformation of this rivet collar, a deformation of the dome-like portion in such a way that the diameter of the joint opening is reduced, but does not take place. The anchoring of the functional element is carried out solely by riveting, i. solely in that the deformed rivet collar engages behind the flat material in the region of the joining opening.

In a preferred embodiment of the invention, the molding of the dome-like portion and the riveting is carried out in a single tool, wherein formed in this tool temporally successively first of the dome-like section and then after the forming of this section, the joining and riveting of the functional element take place.

For the purposes of the invention, "flat material" is to be understood as meaning a flat material made of a permanently deformable material, in particular of a metallic material, for example steel, and also a workpiece made of such a flat material.

Under "functional element" are in the context of the invention quite generally understood to be a fastened in such a flat element element, in particular a connecting element, such. B. a nut, a bolt or the like.

Fig. 1

in vereinfachter Darstellung und im Schnitt ein nicht zu der Erfindung gehörendes Funktions- oder Fügeelement in Form einer Nietmutter;

Fig. 2

in vereinfachter Darstellung, teilweise im Schnitt eine nicht von der Erfindung umfasste Verbindung zwischen dem Funktionselement der Fig. 1 und einem Flachmaterial;

Fig. 3

in vereinfachter Darstellung eine Werkzeuganordnung zum Befestigen des nicht zu der Erfindung gehörenden Funktionselementes der Figur 1 in dem Flachmaterial;

Fig. 4

in vergrößerter Darstellung ein Detail einer Werkzeugmatrize;

Fig. 5

in einer Darstellung wie Figur 1 eine weitere mögliche Ausführungsform einer nicht von der Erfindung umfassten Verbindung zwischen einem Funktionselement und einem Flachmaterial;

Fig. 6 und 7

ein nicht zu der Erfindung gehörendes Funktionselement, zusammen mit einem Flachmaterial vor und nach der Herstellung der Verbindung zwischen dem Flachmaterial und dem Funktionselement;

Fig. 8 und 9

in Darstellungen ähnlich Figur 1 weitere Ausführungsformen einer nicht von der Erfindung umfassten Verbindung;

Fig. 10

in vereinfachter Darstellung die Verbindung zwischen einem aus einem metallischen Flachmaterial, beispielsweise aus Stahlblech hergestellten Werkstück und einem als Nietmutter ausgebildeten Verbindungselement, teilweise geschnitten, bei einer Ausführungsform gemäß der Erfindung;

Fig. 11

das Werkstück der Figur 10 im Bereich einer Vorlochung oder Fügeöffnung für das Verbindungselement;

Fig. 12

in Einzeldarstellung das Werkstück der Figur 10 im Bereich einer Vorlochung oder Fügeöffnung in seiner Formgebung nach dem Fügen;

Fig. 13

das Verbindungselement der Figur 10 in Einzeldarstellung und im Schnitt;

Fig. 14

das Verbindungselement der Figur 13 in einer Draufsicht auf seine den Nietbund aufweisende Stirnseite;

Fig. 15 und 16

Darstellungen ähnlich Figur 14 bei weiteren Ausführungsformen gemäß der Erfindung;

Fig. 17

in einer Darstellung ähnlich Figur 13 eine weitere mögliche Ausführung eines Verbindungselementes in Form einer Nietmutter;

Fig. 18

in vergrößerter Teildarstellung die Verbindung zwischen einem Verbindungselement und einem aus Stahlblech hergestellten Werkstück gemäß einer weiteren Ausführungsform der Erfindung.

The invention will be explained in more detail below with reference to the figures of exemplary embodiments. Show it:

Fig. 1

in a simplified representation and in section a not belonging to the invention functional or joining element in the form of a rivet nut;

Fig. 2

in a simplified representation, partly in section a not included in the invention connection between the functional element of Fig. 1 and a sheet;

Fig. 3

in a simplified representation of a tool assembly for attaching not belonging to the invention functional element of FIG. 1 in the sheet;

Fig. 4

an enlarged view of a detail of a tool die;

Fig. 5

in a presentation like FIG. 1 a further possible embodiment of a not included in the invention connection between a functional element and a flat material;

6 and 7

a not belonging to the invention functional element, together with a flat material before and after the preparation of the connection between the sheet and the functional element;

8 and 9

similar in representations FIG. 1 further embodiments of a compound not covered by the invention;

Fig. 10

in a simplified representation, the connection between a workpiece made of a metallic sheet, for example made of sheet steel and a connecting element designed as a rivet nut, partially cut, in an embodiment according to the invention;

Fig. 11

the workpiece of FIG. 10 in the region of a pre-perforation or joining opening for the connecting element;

Fig. 12

in detail the workpiece of the FIG. 10 in the area of a pre-perforation or joining opening in its shape after joining;

Fig. 13

the connecting element of FIG. 10 in individual representation and on average;

Fig. 14

the connecting element of FIG. 13 in a plan view of his rivet collar having end face;

FIGS. 15 and 16

Representations similar FIG. 14 in further embodiments according to the invention;

Fig. 17

similar in a presentation FIG. 13 Another possible embodiment of a connecting element in the form of a rivet nut;

Fig. 18

in an enlarged partial view, the connection between a connecting element and a workpiece made of steel sheet according to another embodiment of the invention.

The FIGS. 1 to 9 represent not belonging to the invention examples.

The following, to the FIGS. 1 to 9 the corresponding description therefore relates to objects not covered by the invention. In the Figures 1 - 3 are 1 one Flat material made of a permanently deformable material, such as a metal or steel sheet and 2, a functional element in the form of a rivet nut, according to the Fig. 2 is held in the flat material 1 by joining and riveting. The functional element 2 is made of a suitable for such elements metallic material, for example made of steel, with a flange portion 3, which has a circular cylindrical peripheral surface in the illustrated embodiment, with a on the in the FIG. 1 upper end face 4 of the flange portion 3 wegstehende mounting portion 5 and with a on the in the FIG. 1 lower end face 6 wegstehende in the not yet riveted state hollow or circular cylindrical Nietbund 7, the outer diameter as well as the outer diameter of the mounting portion 5 is smaller than the outer diameter of the flange 3. The cylindrical outer surfaces of the sections 3 and 5 and the Nietbundes 7 in the not yet riveted state are each provided concentrically to the common axis FA of the functional element 2. 8 with a preferably provided with an internal thread at least open at one end hole is designated, which is coaxially formed with the axis FA in the flange 3 and in the mounting portion 5 and whose diameter is smaller than the inner diameter of the Nietbundes 7 in the not yet riveted state.

Where the functional element 2 is fixed in the flat material 1, a joining opening 9 is introduced into this flat material. Furthermore, the flat material 1 is permanently deformed in the region of this joining opening 9 in such a way that the dome-shaped section designated 10 forms a circular, planar or essentially flat base 11, in the center of which the joining opening 9 is provided and that of the plane of the flat material 1 is spaced. In the illustrated embodiment, the plane of the base 11 is parallel or approximately parallel to the plane of the sheet 1. The joining opening 9 has a diameter which is approximately equal to the outer diameter of the Nietbundes 7 in the non-riveted state, but less than the diameter of the base 11, which is equal to or approximately equal to the outer diameter of the flange portion 3 in the illustrated embodiment. With 12 of the frustoconical edge of the section 10 is designated. If the joining opening 9 is produced before the molding of the dome-like section, then this takes place in such a way that the diameter of the joining opening 9 is equal to or greater than the outside diameter of the rivet collar 7 already in the as yet unformed flat material 1.

The functional element 2 is joined to the flat material 1 after the dome-shaped section 10 has been formed by riveting, ie by increasing (joining) the rivet collar 7 into the joining opening 9 and by simultaneously deforming the rivet collar 7 in such a way that the joining opening 9 surrounding area of the base 11 between the deformed rivet collar 7.1, which is located on the concave side of the dome-shaped portion 10, and the end surface 6 forming the abutment surface for the sheet 1 is clamped on the convex side of the dome-shaped portion 10. This in the FIG. 2 generally denoted by 13 connection between the sheet 1 and the functional element 2 without reshaping of the dome-shaped portion 10 and without a reduction in the diameter of the joint opening 9. Since the latter is provided in the planar base 11 and the deformed rivet collar 7.1 this flat base 11 in Area of the joining opening 9, that engages behind the lower surface of the sheet 1 and thus within the dome-shaped portion 10, a high pull-out strength is achieved for the functional element 2 against acting in the direction of the axis FA forces (arrow A), especially since the folded or deformed Nietbund 7.1 extends with its relative to the axis FA radially outward area to the immediate vicinity of the transition between the planar base 11 and the edge 12.

By fastening the functional element 2 in the region of the dome-shaped section 10, it is further ensured that the deformed rivet collar 7.1 can form optimally during riveting and this deformed rivet collar 7.1 also does not protrude beyond the side of the flat material 1 facing away from the flange section 3 or the workpiece formed by this flat material.

The FIG. 3 shows a tool assembly 14, with which the molding of the dome-shaped portion 10 in the region of the already prepared in the sheet 1 joining opening 9, the joining of the functional element 2 and the Nietbundes 7 and riveting done in a single tool. For this purpose, the tool arrangement 14 consists of a lower tool 15, which forms with its upper side a planar contact or bearing surface for the underside of the flat material 1. In a recess 16 open towards the support surface of the lower tool 15, a die 17 is inserted, which protrudes with its upper end on the support surface 16 and there an annular, the die and tool axis WA enclosing Matrizenbund 18 and in the middle a frustoconical, rounded rivet head 19 forms, which is also arranged with its axis coaxially with the axis WA. Between the rivet head 19 and the rivet collar concentrically closing this rivet collar 18, the female mold 17 is formed with a groove-like, the axis WA annularly enclosing recess 20 which relative to the axis WA radially outwardly of Matrizenbund 18 and radially inwardly limited by the conical surface of the rivet head 19 is. In the illustrated embodiment, the Matrizenbund 18 has an approximately square or rectangular ring cross-section with slightly rounded edge regions.

The distance with which the matrix collar 18 protrudes beyond the plane of the contact surface 16 is denoted by x1 ( Fig. 4 ). The distance at which the Matrizbund 18 projects beyond the level of the bottom of the annular recess 20 is designated by x2. In the illustrated embodiment, x1 is greater than x2. The distance x1 essentially determines the height of the dome-shaped section 10. The distance x2 essentially determines the clearance between the die 17 and the underside of the sheet 1 during riveting. The measure x1 - x2 is approximately equal to the distance that the deformed rivet collar 7.1 has from the bottom of the adjacent to the dome-shaped portion 10 flat material 1.

The tool assembly 14 further comprises an annular, for example spring-loaded hold-down 21, which is arranged coaxially with the tool axis WA and in the direction of this tool axis u. a. also for clamping the flat material 1 with its annular hold-down surface 22 on the lower tool 15 can be lowered. At the planar, annular hold-down surface 22, the hold-down 21 has an inner diameter that is greater than the outer diameter of the Matrizenbundes 18, by an amount which is greater than twice the material thickness or thickness D of the sheet 1. Above the hold-down surface 22nd In the illustrated embodiment, the inner diameter of the blank holder 21 above the hold-down surface 22 is approximately equal to the inner diameter of the rivet collar 18. Between the inner surface 23 and the hold-down surface 22 is the Hold-down 21 performed with a clearance forming annular recess 24 which is open both on the hold-down surface 22, and on the inner side 23 of the hold-21. In the direction of the axis WA, the recess 24 has a dimension which is greater than the dimension x1.

In the hold-down 21 and relative to this, a punch 25 is provided axially movable in the direction of the axis WA. This punch 25 as well as the hold-down 21 part of an upper tool, for example part of a punching head, and is actuated by an actuator, for example by a movable up and down tool holder of a tool assembly 14 press. The punch 25 is formed on its side facing the tool lower part or the die 17 facing side so that there each with the flat material 1 to connecting functional element 2 is held and carried with the sinking punch 25.

• Das Flachmaterial 1 wird bei angehobenem Niederhalter 21 und Stempel 25 in die Werkzeuganordnung 14 eingelegt, und zwar derart, dass die in dem dann noch flachen Flachmaterial 1 bereits vorgelochte Fügeöffnung 9 mit ihrer Achse möglichst genau achsgleich mit der Werkzeugachse WA angeordnet ist. Dies kann beispielsweise durch am Werkzeugunterteil vorgesehene Positionierelemente, beispielsweise Positionierstifte erreicht werden, die mit Positionierbereichen, beispielsweise mit Positionieröffnungen im Flachmaterial 1 zusammenwirken.

The operation of the tool assembly 14 can be described as follows:

• The flat material 1 is placed in the tool assembly 14 with raised downholder 21 and punch 25, in such a way that in the then flat sheet 1 already pre-punched joint opening 9 is arranged with its axis as closely as possible coaxially with the tool axis WA. This can be achieved, for example, by positioning elements provided on the tool lower part, for example positioning pins, which interact with positioning areas, for example with positioning openings in the flat material 1.

After inserting the sheet 1 in the tool assembly 14, the upper tool is lowered. Here comes first the hold-down 21 with its hold-down surface 22 to rest against the top of the sheet 1, so then on the Matrizenbund 18 of the dome-shaped portion 10 is formed, possibly even with the participation of the Matrizenbund 18 opposite surface of the recess 24. After the complete Lowering the hold-down 21 and after complete molding of the dome-shaped portion 10 in the now between the holddown 21 and the die 17 surrounding annular region of the support surface 16 clamped flat material 1 is supplied with the punch 25, the functional element 2 with the Nietbund 7 ahead. This or its material then passes increasingly through the joining opening 9 in the case of plastic material deformation under the flat material 1 and forms the deformed rivet collar 7.1, which is received substantially in the space formed below the flat material substantially by the groove-like recess 20. The joining or riveting operation is achieved by pressing the region of the base 11 surrounding the joining opening 9 between the surface and the upper side the base 11 adjacent end face 6 and the below the sheet material 1 substantially absorbed by the recess 20 deformed Nietbund 7.1 completed.

In order to achieve a rotationally secure anchoring of the functional element 2 in the flat material 1 with the highest possible torque absorption, a plurality of depressions are provided in the illustrated embodiment on the end face 6, into which the material flows from the area surrounding the joining opening during riveting or pressing. Instead of or in addition to the depressions, protrusions may also be provided on the end face 6 which press into the material of the base 11 surrounding the joining opening 9 during riveting.

A special feature of the tool assembly 14 and the method carried out with this tool assembly is that in a single tool and thus in a single operation, the compound 13 is prepared by forming the dome-shaped portion 10 and then joining and simultaneous riveting of Functional element 2 in the region of the joining opening 9.

As stated above, the dimension x1 determines the projection of the matrix collar 18 over the plane of the contact surface 16 and thus the distance between the top of the base 11 and the plane of the top of the sheet 1 outside the dome-shaped portion 10. The dimension x2 determines the distance between the Matrizenbund 18 and the bottom surface of the recess 20 and thus substantially the free space below the sheet 1 for the plastic deformation of the Nietbundes 7 and for the formation of the deformed Nietbund 7.1. The dimension x2 then also essentially determines the projection of the deformed rivet collar 7.1, ie the extent to which this deformed rivet collar 7.1 projects beyond the underside of the flat material 1 in the region of the joining opening 9. The difference x1 - x2 then determines the distance between the plane of the underside of the sheet 1 and the deformed rivet collar 7.1.

The FIG. 5 shows as a further embodiment of the invention, a connection 13a, which differs from the connection 13, inter alia, that the base 11 of the dome-shaped portion 10a has a diameter which is greater than the diameter of the flange portion 3, and the dome-shaped portion 10a on the outer Edge of its base 11 with an annular, the axis FA concentrically enclosing bead 26 is formed, the radially outward into the edge 12 and radially inwardly into the joining opening 9 enclosing plan or substantially planar and oriented parallel to the plane of the sheet portion of the base 11th goes over, which is clamped after riveting between the end face 6 and the deformed Nietbund 7.1. The bead 26 is produced, for example, by a corresponding geometry of the die 17 corresponding to the die or by a short over or further stroke of the punch 25 after riveting of the functional element 2 with at least one of the rivet head 19 having part of the die.

The connection 13a has the additional advantage that the stiffness of the flat material 1 in the region of the connection 13a or in the region of the joining opening 9 is increased by annular bead 26, and this alone improves the pull-out strength of the connection 13a. Furthermore, it is also achieved by the annular bead 26 that tear-out forces acting in the direction of the axis FA or of the arrow A initially lead to an additional tensioning of the functional element 2 on the rivet collar 7.1 in the flat material 1.

The FIG. 6 shows a functional element 27, which differs from the functional element 2 essentially only in that the flange portion 3 does not have a plane end face 6 on its side having the rivet collar 7, but with a Conical surface 28 is formed, which extends in the illustrated embodiment of the circumference of the flange portion 3 to the Nietbund 7 and their axial distance from the free end of the Nietbundes 7 increases with increasing distance from the peripheral surface of the flange portion 3 or its cone angle to the, the rivet collar 7 having side of the functional element 27 opens.

The FIG. 7 shows the connection 13b between the functional element 27 and the flat material 1. This compound, for example, turn with the tool assembly 14 of FIG. 3 realized. When joining and folding the Nietbundes 7 then takes place by the geometry of the recess 28 an additional "Aufklechen" of the sheet in the surrounding the joining opening 9 portion of the dome-shaped portion 10b in the sense of increasing the distance from the plane of the underside of the sheet 1, so after the functional element 27 is additionally held with the undercut formed in the flat material 1 by the conical surface 28 when finishing the connection 13b.

The FIG. 8 shows a compound 13c, which differs from the compound 13b essentially in that in addition the bead 26 is provided, which in turn then generates, for example, by a corresponding formation of the die 17 corresponding die or by an additional further stroke of the punch 25 at yielding die is.

The FIG. 9 shows a connection 13d between the functional element 2 and a flat material 29 of greater thickness D. Instead of the joining opening 9, a joining opening 30 is provided, the diameter of which increases towards the underside of the flat material 29, ie to the side of the flat material 29 facing away from the flange section 3, and Although in the illustrated embodiment step-shaped. The joining opening 30 can be produced in many different ways, for example by punching and stamping or by a conically widening diameter by punching and browsing. For anchoring the functional element 2 of the rivet collar 7 is folded after joining in the widening region of the joint opening 30 or deformed within the joint opening so that the positive connection between the sheet and the functional element 2 results without the deformed rivet collar 7.1 on the underside of the sheet 1 protrudes. In the FIGS. 10-13 101 is again a workpiece made of a metallic flat material, for example of sheet steel, in which a connecting element formed as a rivet nut 102 is held by joining and riveting. The workpiece is provided with a joining opening 103, which is located on the base 104.1 of a dome-like portion 104, which is made of the flat material of the workpiece 101 by permanent or plastic deformation with an edge 104.2 surrounding the base 104.1, which in the illustrated embodiment frusto-conical is formed so that the corresponding cone angle opens to the plane E2 out. With the edge 104.2 of the dome-like portion 104 moves relative to the axis FA of the joining opening 103 in the workpiece 101 outside of the section 104, in such a way that in the illustrated embodiment, the plane E1 of the base 104.1 of the plane E2 of the rest of the workpiece 101st is spaced.

The rivet nut 102, which is also made of a metallic, deformable by rivets material, for example made of steel, essentially consists of a rivet nut body 105 which is formed in the illustrated embodiment on its outer surface circular cylindrical to a rivet nut axis NA and a coaxial with the axis NA arranged, open at both ends bore 106 with female thread. One of the two end faces of the annular rivet nut body 105 forms an end face 105.1 against which the rivet nut 102 abuts against the side 104.1 facing away from the plane E2 after riveting or joining to the workpiece 101. About this face 105.1 is not at 4, a rivet collar 108 is formed, which is hollow cylinder-like and the axis NA concentrically enclosing, with an inner diameter slightly larger than the inner diameter of the threaded bore 106 and having an outer diameter smaller than the outer diameter of the Nietmutterkörpers 105. The axial length of the Nietbundes 108th is slightly smaller than the axial length of the Nietmutterkörpers 105 or the distance between the end face forming 105.1 end face and the opposite end face 105.2 of the Nietmutterkörpers 105. In the illustrated embodiment, the axial length of the Nietbundes 108 about 60 - 70% of the axial length of the rivet nut body 105.

Between the rivet collar 108 and the outer edge of the rivet nut body 105, a depression 109 is introduced into the latter on the end face 105. 1, which surrounds the axis NA in an annular manner. The recess 109 is spaced from the outer edge, so that between the recess 109 and the outer edge of an axis NA concentrically enclosing annular surface 110 is formed, on which the end face 105.1 groove-shaped recesses 111, so that on the annular surface 110 for torque transmission profiling consisting of the recesses 111 and projections formed therebetween is formed. The recesses 111 extend into the recess 109 and extend in the illustrated embodiment in each case to the peripheral surface 107 of the rivet nut body 105 and have a depth which is equal to the depth of the recess 109. The depth of the recess 109 and the recesses 111 may also be different. In particular, it is possible to make the depressions 111 so that they extend into them at a depth greater than the depth of the depression 109, thus resulting in an additional profiling at the bottom of the depression 109.

In the illustrated embodiment, the recess 109 directly adjoins the rivet collar 108 with its inner surface, relative to the axis NA, i.e., the rivet collar 108; the outer surface of the rivet collar 108 merges into the surface of the recess 109. Furthermore, the formation is such that the bottom of the recess 109 is located in a direction perpendicular to the axis NA oriented plane which intersects the bore 106 outside the thread, so that the annular material portion between the surface of the recess 109 and the bore 106 is part of the Riveting deformed rivet collar 108 and the rivet nut 102 on the end face 105.1 forms a step-shaped contact surface, with which it rests against the base 104.1 after riveting and which is composed of the radially outer surface of the recess 109 and the subsequent annular surface 110.

The rivet nut 102 is held by inserting (joining) the rivet collar 108 in the joining opening 103 and by subsequent plastic deformation or by riveting on the workpiece 101 in such a way that the area of the base 104.1 surrounding the joining opening 103 lies between the lower end face 105.1 (in FIGS. including the depression 109) or the step-shaped contact surface formed on this end face 105.1, in particular also formed by the depression 109, and the deformed rivet collar 108.1. In this case, the flat material of the workpiece 101 is correspondingly permanently deformed or plastically deformed in its area immediately surrounding the joining opening 103 of the step-shaped contact surface formed by the recess 109 and the annular surface 110, such that-partly also due to the flow of the material-surrounding the joining opening 103 and formed in the recess 109 frusto-conical edge 103.1 forms, the cone angle opens to the plane E2 towards, under magnification of the cross section of the joint opening 103. Furthermore, during riveting by plastic deformation of the material of the workpiece 101 is a constriction of the edge 103.1, and although approximately where this conical edge 103.1 merges into the rest of the base 104.1. This in the figures designated 112, the joining opening 103 constricting annularly is produced essentially by the deformation of the material of the workpiece 101 between the annular surface 110 and the deformed rivet collar 108.1, but may be interrupted or only reduced where the recesses 111 open into the recess 109. The free edge of the deformed rivet collar 108.1 has in the illustrated embodiment a distance from the axis NA which is equal to or approximately equal to half the diameter of the rivet nut body 105.

The FIG. 12 shows the workpiece 101 in its generated after riveting of the rivet nut 102 shaping, ie with the conical edge 103.1 surrounding the joining opening 103 and with the constriction 112 on the upper side facing away from the plane E2 at the transition of the edge 103.1 in the rest of the base 104.1

By forming during riveting, recorded in the recess 109 conical edge 103.1, which is also tightly surrounded by the material of the rivet nut 102, and by the constriction 112 results in a high pull-out strength for the anchored in the workpiece 101 rivet nut 102 against such forces , which act in the axis NA and at the for the FIG. 10 selected representation are directed upward, ie away from the plane E2. As a result of the projections pressing in during the riveting into the material of the workpiece 101 and formed by the depressions 111, the twist-proof anchoring of the rivet nut 102 with a high torque resistance is achieved.

When riveting in the region of the edge 103.1 possibly displaced material is received in the recess 109 without there being a radially acting to the axis NA pressure ring tension between the edge of the joint opening and the rivet nut 102 and the rivet collar 108.

The rivet nut 102 is joined and riveted in a suitable tool, it being possible to provide the workpiece 101 with the dome-like portion 104 prior to joining the rivet nut 102, or to shape this portion first in the tool, in which also the Riveting the rivet nut 102 takes place. In any case, the workpiece 101 is first provided with the joining opening 103, preferably before molding the dome-like portion 104. Furthermore, the joining opening is made with such a diameter that can be used in the joining of the rivet collar 108 in this opening.

It has been assumed above that the recesses 111 extend to the periphery of the rivet nut body 105. In the FIG. 15 an embodiment is shown in which the recesses 111 terminates at a distance from the peripheral surface of the rivet nut body 105.

The FIG. 16 shows an embodiment in which the recess 109 is surrounded by a projection 109.1 to achieve the twist-secure connection, which has a deviating from the circular shape at its radially outer edge, namely an approximately polygonal course with the peripheral surface 107 convexly curved corners and with intermediate to the peripheral surface 107 concavely curved sides.

The FIG. 17 shows in a presentation like FIG. 13 a rivet nut 102a, which differs from the rivet nut 102 only in that the rivet nut body 105a is integrally formed at its upper end side facing away from the rivet collar 108 and the recess 109 with a protrusion 113 projecting beyond this end face and arranged coaxially with the axis NA, in FIG which continues the threaded hole 106a.

The FIG. 18 shows in a very enlarged partial view the connection between the dome-like portion 104 of the workpiece 101 made of sheet metal with a rivet nut 102b, which differs from the rivet nut 102 in that the recess 109b corresponding to the recess 109 is not provided directly adjacent the rivet collar 108, but surrounds the rivet collar 108 at a distance, ie, the radially inner edge of the recess 109b is spaced from the rivet collar 108. After inserting the rivet nut 102b with the not yet deformed rivet collar 108 in the joining opening 103, the diameter of which in this embodiment again at most equal, but preferably slightly larger than the outer diameter of the non-deformed Nietbundes 108, the Nietbund 108 is in the Nietbund 108.1 deformed such that the material of the workpiece 101 is clamped in the area surrounding the joint opening 103 between the lower, the recess 109b having annular or contact surface of the rivet nut body 105b and the plastically deformed Nietbund 108.1, wherein the material of the workpiece here, among other things plastic or is deformed by flowing into the recess 109b and thereby on the one hand to the plane E2 facing bottom of the base 104.1 a the opening 103 enclosing constriction 114 results and on the other hand, an annular, engaging in the recess 109b bead-like projection 115 facing away from the plane E2 n top of the base 104.1. By the constriction 114 and by engaging in the recess 109b projection 115 also results in this embodiment, a high pull-out force for anchored in the workpiece 101 rivet nut 102b especially against those forces acting in the axis NA and in which for the FIG. 18 selected representation are directed upward, ie away from the plane E2. In order to achieve a torsion-proof anchoring of the rivet nut 102b with high torque resistance, the front side of the rivet nut body 105b having the rivet collar 108 is again structured in this embodiment as well.

All the above-described embodiments have in common that the joining opening 103 is produced with a diameter which is at least equal, but preferably greater, than the outer diameter of the rivet collar 108.

The invention has been described above using the example of rivet nuts. It goes without saying that the invention can also be used with other connecting elements, for example in the case of rivet bolts, which then have the rivet collar 108, the recess 109 and the annular surface 110 provided with the depressions 111 or another profiling on a side of a bolt head forming a front side and in which the bolt shank is beyond this end face, concentrically surrounded by the rivet collar 108.

The invention has been described above in various embodiments. It is understood that numerous changes and modifications are possible within the scope of the claims, without thereby leaving the inventive concept underlying the invention.

It has been assumed above that the joining opening is already introduced into the sheet or flat material 101 at the respective joining area before the forming of the dome-like section. In principle, of course, there is also the possibility of initially forming the dome-like section in the joining region and then introducing the joining opening into its base, again with a diameter which is equal to or slightly greater than the outer diameter of the rivet collar.

LIST OF REFERENCE NUMBERS

1

Sheet metal or flat material

2

functional element

3

Flange portion of the functional element

4

front

5

attachment section

6

front

7

rivet collar

7.1

deformed rivet collar

8th

drilling

9

joining opening

10, 10a, 10b, 10c

dome shaped portion of the sheet

11

Base of the dome-shaped section 10

12

conical edge of the dome-shaped portion 10

13, 13a, 13b, 13c, 13d

connection

14

tooling

15

lower tool

16

Contact or bearing surface on the lower tool 15th

17

die

18

die collar

19

rivet head

20

deepening

21

Stripper plate

22

annular hold-down surface

23

Inner surface of the hold-down 21

24

recess

25

stamp

26

Beading

27

functional element

28

Depression or conical surface

29

flat material

30

joining opening

101

workpiece

102, 102a, 102b

Rivet nut

103

joining opening

104

domed section

104.1

Base

104.2

edge

105, 105a, 105b

rivet nut body

106

threaded hole

105.1, 105.2

front

107

Peripheral surface of the rivet body

108

rivet collar

108.1

deformed rivet collar

109, 109b

deepening

109.1

head Start

110

ring surface

111

deepening

112

constriction

113

head Start

114

constriction

115

Projection or bead

A

pullout

D

Material thickness of the flat material 1 or 29

FA

Axis of the functional element or the joining opening

N / A

Axle of rivet nut 102

WA

tool axis

x1

Projection of the Matrizenbundes 18 over the plane of the contact surface 16

x2

Overhang of the Matrizenbundes 18 over the level of the bottom of the recess 20th

Claims (9)

1. A method for attaching a functional element (102, 102a), for example a connection element, e.g. a riveting bolt or a riveting nut, to a plastically deformable flat material (101) or workpiece, wherein the functional element (102, 102a) has, on an end face (105.1), a riveting collar (108), which projects beyond said face and is formed by a hollow or tubular section, wherein a dome-like section (104) is formed by plastic deformation in a joining region in the flat material (101), wherein said dome-like section projects with its base (104.1) beyond a plane (E2) of the flat material (101) that surrounds said section and has a joining opening (103) in the base (104.1), and wherein the attachment of the functional element (102, 102a) to the flat material (101) is carried out using a joining and riveting process by introducing the riveting collar (108) into the joining opening (103) and by plastically deforming the riveting collar (108) in such a manner that the base (104.1) is received in a region surrounding the joining opening (103) between the deformed riveting collar (108.1) and the end face (105.1) of the functional element (102, 102a),
   Wherein, if a functional element (102, 102a) is used that has at least one depression (109) provided on the end face (105.1) and an annular face (110) surrounding said depression (109), the joining and riveting process is carried out in such a manner that the flat material (101) is deformed into the annular depression (109) by plastic deformation and/or by flowing at an edge (103.1) surrounding the joining opening (103),
   characterised in that
   the joining and riveting process furthermore is carried out in such a manner that the flat material (101) is deformed by the plastic deformation and/or flowing while forming a bead-like protrusion, which is received in the depression (109), and is constricted between the annular face (110), which surrounds the depression (109), and the riveting collar (108.1), wherein the joining and riveting process is carried out without forming a compression ring stress between the edge (103.1) and the functional element (102, 102a, 102b).
2. The method according to Claim 1,
   characterised in that
   the joining and riveting process is carried out in such a manner that the edge (103.1), which surrounds the joining opening (103) and is received in the depression (109), has a shape in the manner of a conical ring, at least after the riveting process, with a cone angle that opens towards a plane (E2) of the flat material (101).
3. The method according to any one of the preceding claims,
   characterised in that
   during the riveting process, at least one profiled portion, which is provided on the functional element (102, 102a), preferably on the end face (105.1) and/or on the riveting collar (108), is pressed into the flat material (101), wherein the at least one profiled portion is formed for example by depressions (111) and/or protrusions.
4. The method according to any one of the preceding claims,
   characterised by the use of
   a functional element (102, 102a) having at least one depression (109, 109b) adjoining the riveting collar (108),
   and/or
   a functional element having an annular depression (109, 109b),
   and/or
   a functional element (102, 102a) having a depression (109) that has, at least in an edge region, a shape that deviates from the circular shape, for example a polygonal shape.
5. The method according to any one of the preceding claims,
   characterised in that
   the joining opening (103) in the respective joining region is introduced into the flat material (1) before the dome-like section (104) is shaped,
   or in that
   the joining opening (103) in the respective joining region is introduced after the dome-like section (104) is shaped,
   and/or in that
   the dome-like section (104) is shaped before the joining and riveting process with a planar or substantially planar base, which surrounds the joining opening (103) and lies in a plane parallel to the plane of the flat material (1) surrounding the dome-like section (104) or perpendicular to the axis of the joining opening (103), and/or in that
   the joining opening (103) is produced with a diameter that is at least equal to the outer diameter of the riveting collar (108).
6. The method according to any one of the preceding claims,
   characterised in that
   the anchoring of the functional element (102, 102a) is carried out in such a manner that the edge region of the joining opening (103) that is received between the deformed riveting collar (108.1) and the end face (105.1) of the functional element (102, 102a) lies in the plane parallel to the plane of the flat material (1) surrounding the dome-like section (104) or perpendicular to the axis of the joining opening (103).
7. The method according to any one of the preceding claims,
   characterised in that
   during the joining and riveting process, the edge region of the base (104.1) that surrounds the joining opening (103) is deformed such that the edge region of the base (104.1) that is clamped between the deformed riveting collar (108.1) and the contact face and surrounds the joining opening (103) is in the form of a conical ring, wherein the edge region surrounding the joining opening (103) is deformed, for example, such that the cone angle of said edge region opens into the dome-like section.
8. The method according to any one of the preceding claims,
   characterised by
   the use of a die arrangement (14) having a bottom die (17), a holder (21) and a stamp (25), wherein the bottom die has a riveting head (19) for deforming the riveting collar (108) and a die collar (18), which surrounds said riveting head (19) and projects beyond a contact face or rest face, which is formed on the first die part (15), for the flat material (1) and shapes the dome-like section (104) together with the holder (21) when the die is closed, and in that, after the dome-like section (104) is shaped by movement of the stamp (25) in the direction of the riveting head (19), the functional element (102, 102a) carried with the stamp (25) is attached by joining and deforming the riveting collar with the riveting head (19).
9. A connection between a flat material (1) and at least one functional element (102a, 102b) produced using the method according to one of the preceding claims.

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